Snow driven by winds approaching 100 mph shut down schools, highways, air travel and businesses in the Pikes Peak region Wednesday and left more than 1,000 stranded in their cars awaiting rescue.

The rapidly intensifying storm — known as a bomb cyclone — caused whiteout conditions for drivers caught in its fury and prompted the governor to call out the National Guard and El Paso County to declare an emergency.

Officials pleaded with people to stay home and off the roads.

"The more people on the road, the higher likelihood of crashes happening today," the Colorado State Patrol warned on Twitter. "We are giving you complete permission, 100 percent guaranteed, no questions asked to STAY HOME TODAY."

The storm started as forecast with heavy rains early Wednesday, turning to snow by late morning as the winds picked up. One gust was measured at a record 97 mph around 1:20 p.m. at the Colorado Springs Airport, which canceled more than 40 flights.

It was a hurricane with a Colorado twist. As the wind roared, snow piled up across the region, with 6 to 10 inches in northern El Paso County and about a foot in Woodland Park.

Even before the storm hit, schools, churches and synagogues and local government waved the white flag, announcing late Tuesday that they didn't plan to open Wednesday. All the region's large school districts and several small school districts on the eastern plains announced they will be closed Thursday as well.

The brunt of the storm fell on northeast Colorado Springs and north to Denver, where, for only the fourth time in its history, Denver International Airport shut down all six runways.

Drivers trying to get home around midday and into the evening were brought to a standstill by blowing snow that reduced visibility not to car lengths but to inches. Some reported they couldn't see even the front of their vehicles.

Drivers simply gave up trying to move in such conditions, making it impossible for plows to get through or for emergency responders to get to them. Colorado Springs police began moving abandoned cars from roadways north and east of the city around 7 p.m. Owners were urged to retrieve them as soon as weather allowed. Otherwise they would be tagged and impounded, police said.

With a backlog of hundreds of drivers asking for help, the chairman of the El Paso County Commissioners, Mark Waller, signed an emergency declaration Wednesday afternoon, giving the county the ability to ask for assistance from state and local governments.

"Regional first responders are doing everything possible to help people in this extreme storm," a county news release said.

Callers overwhelmed the emergency 911 lines, with officials telling anyone needing help to text 911 if they couldn't get through by calling.

It was the same all over the Front Range and on the plains.

Gov. Jared Polis declared a state of emergency and activated the Colorado National Guard for search and rescue operations.

In Douglas County, a patrol car with its lights on, a snowplow and a school bus drove up and down the worst roads, rescuing stranded drivers and taking them to shelters, the Sheriff's Office tweeted.

By mid-afternoon, El Paso County Search and Rescue crews had a 600-call backlog, said Sheriff's Office spokeswoman Jacqueline Kirby.

More than 100 vehicles were stranded in traffic on Voywager Parkway about 4:45 p.m., forcing the road to close between Briargate Boulevard and North Gate Road. Around the same time, northbound Interstate 25 was closed near North Nevada Avenue while police officers tried to get 50 to 100 stuck vehicles turned around and off at East Woodmen Road.

Those who ventured outside often found themselves stuck for hours, with interstates and highways across the state shut down at times because of crashes and near-zero visibility. Because of high winds and drifting snow, I-25 from Monument to south of Denver and Interstate 70 from Denver to Kansas were expected to be closed until at least Thursday morning, the Colorado Department of Transportation said.

U.S. 24 east of Colorado Springs was shut down for parts of Wednesday and Colorado Springs police were trying to get all traffic off northbound I-25 Wednesday night at Fillmore Street.

The unrelenting winds took down trees and power lines. While outages weren't widespread, thousands were without electricity, including 18,000 customers in the Falcon area of El Paso County.

Shelters were opened up for stranded drivers and homeless shelters took in as many people as they could squeeze in, with more in warming shelters. About 2 p.m., more than 300 people were gathered at the Springs Rescue Mission's day center at 5 W. Las Vegas St., which was standing room only, said spokesman Travis Williams.

"We haven't been turning people away — just cramming more and more individuals in to get them out of the elements," Williams said.

Some of the nonprofit's cooks weren't able to reach the shelter due to the storm, so men in the nonprofit's addiction recovery program planned to help to make dinner for the hundreds of homeless people staying the night.

The Salvation Army also allowed families with children to stay during the day at its R.J. Montgomery shelter, 709 S. Sierra Madre St., said Karen Daugherty, who oversees the shelter. About 65 people were there as of about 1 p.m.

Daugherty pleaded with people on the streets to seek shelter indoors.

"My biggest concern is that people won't go to try to find help," she said. "Often times, they're already feeling hopeless." She added that people should "just ask for assistance. If we can't provide it, somebody can."

The R.J. Montgomery Shelter has 120 beds for men and 100 beds for women and families with children. If the shelter reaches capacity for families, then officials there will have to turn people away, giving them blankets and handwarmers, Daugherty said.

The Springs Rescue Mission was expecting to exceed its all-time high of 444 people.

All 17 public school districts in the Pikes Peak region canceled classes Wednesday. Colorado Springs city and El Paso County offices were closed, as were medical offices and military installations.

Colorado Springs even shut the gates on two of its iconic attractions: Garden of the Gods and Palmer Park were closed to visitors Wednesday. The Cheyenne Mountain Zoo opened Wednesday morning but shut down at 1 p.m.

Eighteen of the 27 flights scheduled to leave Colorado Springs on Wednesday were canceled, said airport spokeswoman Aidan Ryan. All 29 arrivals were canceled.

By 1:30 p.m., all runways were closed at Denver International Airport, and more than 1,000 flights were canceled.

In the high country, mountain passes were closing for avalanche control.

The Colorado Avalanche Information Center rated avalanche danger for the Front Range as high and warned people against traveling in slide-prone areas. Natural and human-triggered avalanches "are very likely" and could "break hundreds or thousands of feet wide" and from "thousands of feet above you," the center said.

"With the historic avalanches we've seen lately, please consider that you're usual hiding spots in the thick timber may not be safe," the avalanche center wrote. "You need to consider what's above you, even if it's way above you."

The Gazette's Jakob Rodgers and Liz Forster contributed to this report.